FWIW, I think a light like the Fenix P1D is going to have pretty wicked visibility in something like a 90 degree cone at night. Even more so with night vision, which I would assume is SOP for night rescue (not much point being out there if you can't see).

Considering search patterns, I think this would make a huge difference over no light, or a non-strobe light.

Also, having and looking at the Fenix, I'd say it is likely to be pretty reliable in water. These are sturdy and reasonably constructed little lights.

Also, FWIW, the strobe could really help in the case of a land based rescue, esp. if they were searching by plane/helicopter w/night vision.

That said, as Russ said, the big problem is that you have to hold it. As you get tired and hypothermic, you aren't going to be able to hold it. And you might need your hands for other reasons.

All in all, as I said, it isn't an excuse not to prepare for whatever endeavor you are planning on -- but I do think they are powerful little tools that, as the thread suggests, could go a long way if caught unawares. And the thing is so small, there is no reason NOT to have it on you.

Remember the James Kim story -- at least at one point they used thermal imaging. Obviously a fire would have helped a lot....

-john


Edit: Well, a cell phone *might* do it, but the less effective the tool, the smaller the chance it will make the difference. And a cell phone is very unlikely to be very effective (and easily damaged by salt water).